Fans are praying for Tommy Chong, of “Cheech & Chong” fame, as he faces his latest battle with cancer.

The marijuana maven who created best-selling stoner comedy albums and eight movies with partner Cheech Marin could barely stand last weekend at the Las Vegas Hempfest, where he was given a lifetime achievement award.

Chong, 77, announced three years ago he’d been stricken with cancer. But a month later, he tweeted that a hemp oil treatment was working and that he was “99 percent cancer-free.”

Onstage Saturday, Chong said the cancer had come back “big” and that he was due for major surgery in the coming days.

“I was on the Southwest flight from LA with him,” said one source. “He looked pretty worn out. He was visibly weak and ill.”